The invention concerns a wall or roof of a building, wherein at least one heat controlling element for controlling a temperature in the building is arranged in the wall or the roof to form a segment of the wall or roof, the heat controlling element comprising at least a first section and a second section, the first section comprising a heat collecting and storing material and the second section comprising a heat insulating material, wherein the heat controlling element may adopt a first configuration, in which the first section is directed towards the outside of the building and the second section is directed towards the inside of the building, and a second configuration, in which the second section is directed towards the outside of the building and the first section is directed towards the inside of the building.
Solar energy is being used more and more to control the temperature of buildings. According technologies have become quite sophisticated in the past years. However, solar energy still has many inherent difficulties particularly with regard to costs and additional energy requirements to harness the incoming solar energy. Generally, when controlling temperatures of buildings it has been known to use the so-called green house effect. Further, when using solar energy, voltaic cells converting solar power into electricity or solar furnaces, wherein mirrors concentrate sunlight to a furnace, are being used. It is also known to heat water in tubes by the sun which water is then circulated to storage mediums. Some of these tubes are now insulated in vacuum flasks to maximize efficiency. Another known system to use solar energy is the so-called “trombe wall”. This system works by collecting heat from the sun and storing it in the thermal mass of the wall structure. Over a period of time the heat passes by conductivity and radiation through the wall to the inside spaces of buildings, thereby warming them. Usually, trombe walls are of a specific thickness and weight so that heat collected during the day enters the habitat in the evening and continues to radiate heat during the night. However, with this system there is no way to flexibly control the amount of heat passing through the wall. Accordingly, for example in summer it may be too hot while in winter the wall may even be a negative radiator sucking heat out of the space.
From JP 07-119363 a solar shading device is known comprising a panel which can be rotated in a wall. On one side of the panel a blind, in the form of slats, is provided. In summer, the panel can be positioned in the wall such that the slats are directed towards the outside of the building thus blocking incoming sunlight through reflection. In this way, overheating of the building is prevented. In winter, when the room of the building is heated, the panel is turned by 180° so that the slats face the inside of the room. On the opposite side of the panel, now facing towards the outside of the building, a sheet glass is provided through which the winter sunlight can penetrate thus bringing solar energy into the room. In this way, the heating load of the room is reduced in winter.
Accordingly, with the known panel sunlight can be blocked during summer like with a conventional blind. In winter, the blind (slats) is positioned on the inside of the building thus letting the solar energy into the room. However, the known device can only provide heating of the room when sunlight is actually falling onto the device. If the intensity of sunlight changes, this results in a change in the heating of the building as well. The device can therefore not provide uniform heating of the room. Further, the known device lacks flexibility with regard to controlling the temperature in the building.
Starting from the prior art discussed above, it is an object of the invention to provide a wall or roof of the above mentioned kind, wherein the temperature in a building can be controlled evenly, efficiently and flexibly at low cost.
For a wall or roof of the above mentioned kind the invention solves the object in that the heat controlling element may be connected to the building structure by at least one connecting element so that there is direct thermal contact between the heat controlling element and the building, wherein the connecting element is adjustable between a contacting position for providing direct thermal contact between the heat controlling element and the building structure and an interrupting position for interrupting direct thermal contact between the heat controlling element and the building structure.